Epidemiology and clinical outcomes of light-chain amyloidosis in Sweden: A nationwide population-based study

OBJECTIVES

This study evaluated data from six Swedish national registries to fill current evidence gaps on the epidemiology, clinical burden, and overall survival (OS) associated with light-chain (AL) amyloidosis.

METHODS

Patients newly diagnosed with AL amyloidosis were identified using six linked Swedish nationwide population-based registers. For each case, individuals from the general population were selected and matched with a maximum ratio of 1:5 based on age, sex, calendar year, and county.

RESULTS

846 patients newly diagnosed with AL amyloidosis and 4227 demographically matched individuals were identified. From 2011 to 2019, annual AL amyloidosis incidence increased from 10.5 to 15.1 cases per million. At baseline, patients with AL amyloidosis had a significantly higher disease burden including higher rates of cardiac and renal failure relative to the comparison group. Among patients with AL amyloidosis, 21.5% had incident heart failure and 17.1% had incident renal failure after initial diagnosis. Median OS for patients with AL amyloidosis was 56 months versus not reached in the matched general population comparison group.

CONCLUSION

The incidence of newly diagnosed AL amyloidosis in Sweden increased over time with AL amyloidosis being associated with a higher risk of cardiac/renal failure and all-cause mortality compared with the general population.

A comprehensive overview of AL amyloidosis disease characteristics accumulated over two decades at a single referral center in Korea

BACKGROUND

Characteristics of AL amyloidosis across Asia are not well-described in the literature. Thus, we overviewed the incidence and disease characteristics of AL amyloidosis in Korea.

METHODS

We collected medical records of 302 AL amyloidosis patients and compared survival outcomes by predominant treatment strategy and at four time points: 1995-2003, 2004-2008, 2009-2013, and 2014-2018.

RESULTS

The median age was 62 years (36-83). One hundred forty-one patients were classified as stage III (26.3%) or IV (47.9%). The patients diagnosed between 2014 and 2018 survived longer than those diagnosed at other time points due to the introduction of bortezomib (p < 0.01). In addition, patients who received upfront ASCT survived longer than those who received salvage ASCT or chemotherapy alone (p < 0.01). However, most of the 85 patients who experienced early death within 6 months were older than 75 years, had BMI less than 20, and had a high disease burden.

CONCLUSIONS

The incidence of AL amyloid has increased and survival outcomes have improved gradually, most likely due to introduction of novel agents and upfront ASCT. However, not all patients are suitable for these potent treatment modalities, and avoiding early death within 6 months remains a challenge.

Light Chain Amyloidosis: Epidemiology, Staging, and Prognostication

Amyloidosis is a disorder of protein misfolding and metabolism in which insoluble fibrils are deposited in various tissues, causing organ dysfunction and eventually death. Out of the 60-plus heterogeneous amyloidogenic proteins that have been identified, approximately 30 are associated with human disease. The unifying feature of these proteins is their tendency to form beta-pleated sheets aligned in an antiparallel fashion. These sheets then form rigid, nonbranching fibrils that resist proteolysis, causing mechanical disruption and local oxidative stress in affected organs such as the heart, liver, kidneys, nervous system, and gastrointestinal tract. Here we review the epidemiology of light chain amyloidosis, the staging, and the concomitant prognostication that is critical in determining the appropriate treatment.

Hypovitaminosis D Is Prevalent in Patients With Renal AL Amyloidosis and Associated With Renal Outcome

INTRODUCTION

Vitamin D deficiency is common, but no data have been reported on vitamin D levels in light chain (AL) amyloidosis.

PATIENTS AND METHODS

In this exploratory study, stored serum samples from 173 patients with newly diagnosed AL amyloidosis were analyzed for vitamin studies which included 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)₂D] and vitamin D binding protein (DBP). Measurements were made by liquid chromatography-tandem mass spectrometry. Kidney survival and overall survival (OS) were assessed in association to vitamin D status.

RESULTS

Cardiac and kidney involvement occurred in 69% and 63% of patients, respectively. 25(OH)D deficiency (<20 ng/mL) was seen in 56.6% of the patients and was notably found among patients with heavy proteinuria (96%), hypoalbuminemia (84.3%) and morbidly obese patients (68.3%). Heavy proteinuria (>5 gr/24-h) and vitamin D supplementation were independent predictors of 25(OH)D level on nominal multivariate regression analysis. 1,25(0H)₂D deficiency was noted in 37.6% of patients and was independently associated with low eGFR and hypoalbuminemia. Progression to ESRD occurred in 23.7% of evaluable patients. Patients who progressed to ESRD had lower serum 25(OH)D and 1,25(OH)₂D levels compared to those who did not progress to ESRD. On a multivariate analysis, severe 25(OH)D deficiency was an independent predictor of progression to ESRD as was renal stage, while 1,25(OH)₂D deficiency was not.

CONCLUSIONS

Hypovitaminosis D is common in AL amyloidosis, particularly among patients with heavy proteinuria. Severe 25(OH)D deficiency at time of diagnosis predicts progression to ESRD.

Misconceptions and Facts About Cardiac Amyloidosis

Cardiac amyloidosis is an important clinical entity associated with significant morbidity and mortality. Although the signs and symptoms can be apparent early in the disease course, diagnoses are often made late because of inadequate recognition. A diagnosis of cardiac amyloidosis requires careful scrutiny of a patient's symptoms, an electrocardiogram, and imaging studies, including echocardiography and magnetic resonance imaging. Further evaluation is required through the measurement of serum and urine light chains and the use of bone scintigraphy imaging to differentiate transthyretin amyloidosis from light-chain cardiac amyloidosis. The available treatments have expanded tremendously in recent years and have improved outcomes in the population with this disorder. Thus, it has become increasingly important to diagnose cardiac amyloidosis and provide timely therapies. This article will clarify the various misconceptions about cardiac amyloidosis and provide a framework for primary care providers to better identify this disease in their practice.

Haematologic responses and survival do not significantly decrease with subsequent lines of therapy in systemic immunoglobulin light chain amyloidosis: results from an analysis of real-world longitudinal data

Systemic immunoglobulin light chain amyloidosis (AL) is an incurable disorder, and the natural history is incompletely understood. In this study, we describe its natural history based on an analysis of real-world longitudinal data. All patients seen at the National Amyloidosis Centre, UK, between February 2010 and August 2019 and treated with up-front bortezomib are included. In all, 1 276 patients received the first-line treatment; 259, 85, and 32 patients received second, third, and fourth treatment lines, respectively. Among patients requiring further treatment after the first line, 77·2% started the second line within two years of the first line; 50·5%, 50·6%, 40·1% and 40·6% of patients had achieved at least very good partial response after the first, second, third and fourth treatment lines. Median overall survival (OS) from first, second, third and fourth lines was 45 months, 56 months, 37 months and not reached, respectively (P = 0·109). In summary, although relapses occur in AL amyloidosis, the outcomes and responses do not worsen with each subsequent relapse, making it attractive to design therapeutics with curative intent.

Emerging therapy in light-chain and acquired transthyretin-related amyloidosis: an Italian single-centre experience in heart transplantation

AIMS

The prognosis for patients affected by light-chain cardiac amyloidosis and acquired transthyretin-related (TTR) amyloidosis is poor. Heart transplantation (HTx) could improve prognosis also enabling autologous stem cell transplantation (ASCT) in the first group.

METHODS AND RESULTS

A total of 36 patients affected by systemic amyloidosis have been referred to our centre from 2009 to 2019. Of these, nine had cardiac involvement: seven by light-chain amyloidosis and two by acquired TTR amyloidosis. None died while waiting for HTx. A specific internal protocol useful to select candidates and to monitor the organ involvement after HTx was developed. Median age at diagnosis was 54 years and 66% were male. The most common short-term complication after HTx was renal failure (44%), followed by acute cardiac rejection more than 2R (22%). ASCT was performed in six out of seven light-chain cardiac amyloidosis patients, with a median time of 6 months after HTx. Two patients affected by light-chain cardiac amyloidosis died due to amyloidosis relapse: one before undergoing ASCT. After a median follow-up of 31 (7-124) months, 1- and 5-year survival was 88 and 66% in the cardiac light-chain amyloidosis group. Conversely, 1- and 5-year survival was 100% in the acquired TTR amyloidosis group.

CONCLUSION

HTx may represent a valuable option in carefully selected patients. ASCT after HTx is an effective treatment that could decrease amyloidosis relapse in light-chain cardiac amyloidosis patients. A multidisciplinary approach is mandatory to select the best candidates and to obtain the most effective results with a specific surveillance follow-up protocol.

Characterization and prognostic implication of delayed complete response in AL amyloidosis

INTRODUCTION

Little is known on continued response following completion of therapy in light chain (AL) amyloidosis.

METHODS

We studied 373 AL amyloidosis patients who achieved complete response (CR) or very good partial response (VGPR) to first-line therapy.

RESULTS

By end of therapy (EOT), 46% of patients achieved a CR and 54% a VGPR. With no further therapy, 17.5% of patients were upstaged from VGPR to CR (delayed CR), with a median of 9 months. Compared with CR and VGPR at EOT, patients with a delayed CR were characterized by higher proportion of t(11;14) and lower rate of trisomies. Autologous stem cell transplant was more frequent in the delayed CR group. Patients with a delayed CR were characterized by minimal residual disease negativity and organ response rates similar to patients with CR at EOT and higher than patients achieving VGPR at EOT. Patients with a delayed CR had a longer PFS/OS compared to patients with CR or VGPR by EOT (median PFS 149 vs 92 vs 52 months, P < .001; 10-year OS 87% vs 71% vs 56%, P < .001).

CONCLUSIONS

This study characterizes delayed CR in AL amyloidosis, highlights its prognostic impact which is at least similar to those who achieved CR at EOT, and underlines another aspect of response monitoring.

Incidence of AL Amyloidosis in Olmsted County, Minnesota, 1990 through 2015

OBJECTIVE

To determine the incidence of immunoglobulin light chain amyloidosis (AL amyloidosis) in a strictly defined geographic area from 1990 through 2015.

PATIENTS AND METHODS

We searched a computerized database for the records of all Olmsted County, Minnesota, residents with a diagnosis of AL amyloidosis from January 1, 1990, through December 31, 2015. In addition, records of all residents with a mention of amyloidosis were obtained from the Rochester Epidemiology Project, which contains the medical records of Mayo Clinic and Olmsted Medical Group. The diagnosis of AL amyloidosis was determined by mass spectrometry, immunohistochemical analysis, or positive Congo red staining.

RESULTS

Thirty-five patients were identified as having AL amyloidosis. The median age at diagnosis was 76 years (range, 38-90 years), with men accounting for 54%. The incidence rate of AL amyloidosis from 1990 through 2015 adjusted for age and sex was 1.2 per 100,000 person-years (95% CI, 0.8-1.6 per 100,000 person-years). Rates were similar across the decades 1990-1999, 2000-2009, and 2010-2015 at 1.1, 0.9, and 1.6 per 100,000 person-years, respectively, with no suggestion of an increasing rate during the 26 years. There was a trend toward an increasing incidence over time from 1950 through 2015 in Olmsted County, but it was not significant (P=.15). Applying the rate of 1.2 per 100,000 person-years to the US population of 321 million in 2015, one would expect 3852 new cases of AL amyloidosis in the United States each year.

CONCLUSION

The incidence of AL amyloidosis in Olmsted County has not changed significantly in the past 66 years.

Disease burden of systemic light-chain amyloidosis: a systematic literature review

INTRODUCTION

A systematic literature review on systemic light chain (AL) amyloidosis was conducted in order to understand the disease burden, and identify unmet medical needs and knowledge gaps.

METHODS

MEDLINE, Embase and Cochrane databases were searched for English language studies published in the last 10 years using search terms that focused on the clinical, economic, and patient-reported outcome (PRO) aspects of AL amyloidosis. There was a low yield of articles in the economic and PRO categories and additional searches were conducted in clinical conference proceedings, and using Google and Google Scholar. After review, there were 65 articles included for data extraction.

RESULTS

AL amyloidosis is a rare disorder without any FDA or EMA approved indications for drug therapy. Using off-label therapies, there is a high rate, 42-64%, of non-response or progression, and an associated high mortality. Toxicities during therapy are common with estimates of up to 30-40% of patients experiencing severity of grade 3 or higher. Patients with AL amyloidosis report severe psychological distress, anxiety and clinical depression.

CONCLUSIONS

There is a deficiency in the literature on the economic costs associated with AL amyloidosis, and information on costs has been derived from studies that examined multiple myeloma or other disease or treatment components common to AL amyloidosis.